Now, known is a means for performing the magnetic recording/reproduction on and from both sides of a floppy disc as shown in FIG. 7.
That is, a pair of head sliders 2, 3 are provided in opposed relation to each other so as to sandwich the floppy disc 1 therebetween under a predetermined force, and magnetic head portions 4, 5 embedded in the respective head sliders 2, 3 come into contact with the floppy disc 1 under predetermined surface pressures for magnetic recording and reproducing. The head sliders 2, 3, being made of a ceramic material, tightly wrap the magnetic head portions 4, 5 and the surfaces thereof coming into contact with the floppy disc 1 are ground smoothly.
In the magnetic recording/reproducing apparatus arranged thus, the recording/reproducing characteristic greatly depends upon the contact state between the magnetic heads 4, 5 and the magnetic recording medium. For example, in a case where the degree of the flatness of the floppy disc 1 is low, difficulty is encountered to in excellently performing the recording/reproducing because of not allowing the floppy disc to reform sufficiently between the pair of upper and lower head sliders 2, 3 so that the magnetic head portions 4, 5 are brought into contact with the floppy disc 1.
Such a problem is remarkable in the case of increased recording density. That is, as the recording density is higher, smaller gaps at the contact portions between the magnetic heads 4, 5 and the floppy disc 1 are required to be kept stably, and it is required to increase the degree of the flatness of the floppy disc 1 or to improve the relative position accuracy between the floppy disc 1 and the heads 4, 5. However, there are problems in that the manufacturing cost becomes higher, and the reproducing force for actually allowing the magnetic recording/reproducing cannot be obtained.
On the other hand, the inventors and the other persons have already proposed a magnetic recording/reproducing apparatus (Japanese Patent Provisional Publication No. 62-52759) in which, as shown in FIG. 8, a disc-like magnetic recording medium 6 rotationally driven about a drive shaft is sandwiched from the upper and lower surfaces thereof by means of a pair of magnetic head devices 7, 8 with a predetermined contact pressure. The magnetic head device 6 comprises magnetic head chips 9, 10 and slider pads 11, 12 provided so as to surround the magnetic head chips 9, 10 at a predetermined interval, and the top portions of the magnetic head chips 9, 10 protrude by predetermined amounts with respect to the surfaces of the slider pads 11, 12 which come into contact with the medium.
FIG. 9 is a perspective view of the magnetic head device of FIG. 8 and shows the outline of the configuration of the slider pad 12. Furthermore, FIG. 10 shows another example of the magnetic head device which has a substantially circular slider pad surface 14, a magnetic head chip 13 being provided in the inside of the slider pad surface 14 so that the top portion protrudes by a dimension .delta. (which will hereinafter be referred to as head protruding amount) from the slider pad surface 14.
In a magnetic recording/reproducing apparatus, another magnetic head device having the same configuration as the illustrated magnetic head device 15 is combined therewith so as to sandwich both surfaces of the floppy disc 6 therebetween as well as the case of FIG. 8.
In the example shown in FIG. 10, a non-woven fabric 16 adheres to the slider pad surface 14 to decrease the sliding friction between the floppy disc 6 and the sliding pad. In this case, it is not required that the sliding pad body be made of a ceramic such as barium titanate which is difficult to be machined.
Here, in the case of the above-mentioned arrangement, in order to realize an excellent contact between the magnetic head chip and the floppy disc, it is required to keep the part accuracy high and the part-assembling accuracy, i.e., the interval between the magnetic head chips provided up and down through the floppy disc, the intervals between the magnetic head chips and the slider pads in the respective magnetic head devices, the surface configurations of the magnetic head chips slidably coming into contact with the floppy disc and the slider pads, the positions of the magnetic head chips with respect to the floppy disc, the head protruding amount .delta., and so on. However, in the actual producing place, this is at variance with real conditions from the viewpoint of increase in cost.
On the other hand, in the conventional magnetic recording/reproducing apparatus shown in FIG. 7, as a method for performing the relative positioning of the upper and lower magnetic heads, a reference signal is recorded in advance on a predetermined track of the floppy disc and read by means of a non-adjusting head. The shifting amount from the normal relative position of the upper and lower heads and the angular difference of the magnetic head chip with respect to the recording track are decided on the basis of the reproduction signal. In the case that this method is employed for the magnetic recording/reproducing apparatus as shown in FIG. 8, as compared with the magnetic recording/reproducing apparatus as shown in FIG. 7, as adjusting items are added the head protruding amount (e.g., for medium-travelling directions of the magnetic head chips and the magnetic head devices, for position of the medium seek direction and so on, difficulty is actually encountered in performing the adjustment using the above-mentioned method.